11) (a) The negative sign of a(H7) of IV conflicts with the work of Kochi, Bakuzis, and Krusic,™ in which a(H7) of IV was suggested to be positive to explain its unusual temperature dependence. However, the temperature dependence of a(H7) of IV (with negative sign) may be explained (1) by assuming a broad anharmonic single-minimum potential for the out-ofplane vibration of the C7H7 bond or (2),1b by assuming an asymmetrical broad double-minimum potential with a low barrier to the inversion of the C7-H7 bond; (b) suggested by P. J. Krusic. ( 12) Cf. T. Kawamura, T. Koyama, and T. Yonezawa, J. Am. Chem. Soc., 95, 3220 (1973), and also ref 10. (13) This interchanges the assignment suggested by Kochi, Bakuzis, and Krusic1b of the vinylene and bridgehead protons of IV. We suggest the assignments of a(H2) = 1.20 and a(Hi) = 1.54 G for IV.
Der aus dem Dibromid (Ia) mit Butyl‐Li/DMF erhältliche Dialdehyd (Ib) wird mit Na‐boranat zum Diol (Ic) reduziert, aus dem mit HBr/Eisessig das Bis‐brommethyl‐Derivat (Id) erhalten wird.
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